The object of the research is to determine how and where slow and rapid eye movements are generated. Specifically, we intend to localize the neural mechanism responsible for generating rapid eye movements in all directions. We postulate that this mehanism is located in the reticula formation of the rostral pons. We also intend to study an integrator whose state or output is associated with the vestibular nuclei and the prepositus nucleus, and determine how it is utilized for the production of slow eye movements. This integrator appears to be a focus for the interaction between the visual and vestibular systems. Experiments will be done in alert monkeys. The animals will receive visual and vestibular stimulation before and after lesions. Vestibular stimuli will consist of constant velocity and sinusoidal rotation about vertical and horizontal axes. These stimuli will induce optokinetic nystagmus (OKN), optokinetic after-nystagmus (OKAN), and per and post rotatory nystagmus. Pursuit eye movements will be elicited by sinusoidal movement of tracking targets. Extracellular unit activity and eye movements will be analyzed in the time frequency domains and compared to predictions made from control systems models of the oculomotor system. Eye movements and unit activity before and after lesions will also be studied. This research should help elucidate the underlying organization of the oculomotor system for rapid eye movements in all planes. It should also lead to better understanding of the neurons in the brainstem which perform integration necessary to produce slow eye movements.